It is well known to provide afterburner systems on turbojet engines and such systems typically comprises means to inject fuel into the gas stream mixture, downstream of the turbojet engine turbine and means to ignite the mixture. In turbofan engines, the afterburner system is usually located downstream of the point at which the hot flow of gases and the radially outer colder flow converge. By igniting the additional fuel and the exhaust gas stream, additional thrust is provided to the engine.
Although the afterburner theory is relatively simple, it has proven most difficult to achieve a complete burning of the fuel and to provide a stable flame front for the ignition of the gases. Various attempts have been made to increase the efficieny of the afterburner systems. The patent to Vdoviak (U.S. Pat. No. 3,931,707) illustrates one such attempt. The structure set forth in this patent utilizes an annular passage upstream of a generally "V" shaped flameholder ring to induce a circumferential swirl by a plurality of flow vanes disposed in this annular passage. However, this structure increases the complexity of the afterburner system thereby not only increasing the overall weight of the turbojet engine, but also increasing its maintenance and decreasing the overall reliability.